Playback data is created for testing a server. Recorded data that includes transactions executed in a session established between a client and a server at a designated point in time is extracted. A reduction process that includes deleting data related to certain transactions from the extracted recorded data is performed. The certain transactions are part of a specific transaction group which includes transactions that were executed on or before the designated point in time and includes a transaction that was executed without requiring the execution of a predetermined prior transaction. The playback data is output.